| 摘要 |
PURPOSE:To produce an F10T class high rusting resistant bolt, nut and washer free from the need of coating for rustproofing as the one for fastening steel structures such as a bridge. CONSTITUTION:A stainless steel wire rod having a compsn. contg., by weight, 0.16 to 0.19% C, 0.20 to 0.50% Si, 0.20 to 0.50% Mn, 0.02 to 0.60% Ni, 11.5 to 13.5% Cr, 0.02 to 0.60% Mo, Cr+Mo+1.5Si: 12.5 to 14.3%, Ni+30C+0.5Mn: 5.20 to 6.40% and Cr+2.4Mo: 12.3 to 14.5% is worked into a bolt, nut and washer, is hardened from the temp. range of 920 to 970 deg.C and is next subjected to tempering treatment in the temp. range of 500 to 570 deg.C, by which the F10T class high rusting resistant bolt, nut and washer can be obtd. Furthermore, the thread part and bearing surface part of the nut is coated with a lubricant obtd. by adding 5 to 30% tetrafluoroethylene resin to polyethylene wax, by which the fastening in which the temp. dependency of the torque coefficient is low is made possible. |
